It has been a long tradition that highly skilled perfumers carefully select fragrance oils to blend into a fragrance composition in order to provide a desired and long-lasting fragrance or scent with each application. In so doing, they need to bear in mind differences in the individual character, volatility, and/or odour detection threshold of the fragrance materials that are the components of the full fragrance. Conventional perfuming compositions have fragrance profile characterized by the presence of low volatile fragrance materials and volatile fragrance materials. The low volatile fragrance materials are known as “base notes”, while the volatile fragrance materials can be further divided into high volatile fragrance materials, identified as “top notes” or “head notes”, and medium volatile fragrance materials, identified as “middle notes” or “heart notes”.
The top notes tend to smell citrusy, green, light, fresh, and quickly evaporate due to their high volatility. Top notes are characterized by vapor pressure >0.1 Torr (Calculated using Advanced Chemistry Development (ACD/Labs) Software V11.02 ©1994-2013 ACD/Labs)). Middle notes are associated with floral aromas (e.g., jasmin, rose), fruity, marine or spicy aromas, and have an intermediate volatity in the vapor pressure range of 0.001 to 0.1 Tort Base or bottom notes are characterized as animalic, woody, sweet, amber or musky, not being very volatile, and having a vapor pressure <0.001 Torr.
In addition to the volatility, another important characteristic of a perfume raw material is its olfactory detection level. If a perfume raw material has a low odour detection threshold, otherwise known as “high odour impact”, only very low levels are required of the perfume raw material within a fragrance composition for it to be detected by the user, sometimes as low as a few parts per billion (i.e., ≦50 ppb). Conversely, if a perfume raw material has a high odour detection threshold (i.e., ≧50 ppb), otherwise known as a “low odour impact”, larger amounts of that material are required before it can be smelt by the user.
Conventional perfuming compositions can provide desirable scents initially, but over time consumers can become habituated to the perfume raw materials (PRMs) that form the fragrance. This means after a long period of time, the users and people around them can no longer detect the fragrance. Typically, the habituation problem can be found with perfume raw materials that are less volatile. That may be because the top notes are too volatile and linger around for so little time that the consumers do not have sufficient exposure to trigger the habituation effect. Whereas heart and base notes are on the skin and in the air around the consumer for long periods of time and therefore have ample time to induce habituation.
To overcome the habituation effect and allow consumers to continue to perceive the original scent, particularly over very long periods of time, consumers can: (1) use increasingly larger volumes of the fragrance composition; (2) continually re-apply the fragrance composition throughout the course of the day/evening, and/or (3) switch to a new fragrance composition containing different perfume oils for a significant period of time to reverse the habituation.
However, none of these solutions are particularly desirable. Option (1) can result in an an initial scent that is overpowering and possibly even offensive to the users and/or people around them. Option (2) tends to be costly and may not work since fragrance habituation of the perfume can lead to a diminished perception of the desired scent by the consumers, even when the quantity of the perfume material in the fragrance composition remains consistent and/or increases. The last solution is not particularly appealing either, especially, since many consumers have a signature perfume that they are known for and do not wish to switch.
Accordingly, there remains a need for an improved fragrance compositions that provide long-lasting and desirable scents that can reduce and/or eliminate the fragrance habituation effect in consumers, preferably over long periods of time. It is desirable that the solution to the habituation effect does not require consumers to modify their normal usage habits. It is further desirable to formulate a fragrance composition having improved longevity of the fragrance character, preferably components derived from the less volatile perfume raw materials (i.e., 0.1 to 0.001 Torr or ≦0.001 Torr) and/or having a low odour detection threshold (i.e., ≦50 ppb), preferably over long periods of time.